/Engine/Source/Runtime/Engine/Classes/Materials/MaterialInstanceDynamic.h
This overrides does the remapping before looking at the parent data.
virtual float GetTextureDensity ( [FName](API\Runtime\Core\UObject\FName) TextureName, const struct [FMeshUVChannelInfo](API\Runtime\Engine\FMeshUVChannelInfo) & UVChannelData ) const